Various systems have been implemented or proposed for delivering electronic television program guides (EPOs) to viewer locations. Such approaches include use of the vertical blanking interval (VBI) portion of a broadcast television station signal, use of a paging network, and through dial-up telephone. Each of these methods presents shortcomings. VBI access may be controlled by cable companies which may place restrictions on such transmissions. Paging receivers and paging airtime are relatively expensive, and dial-up telephone service ties up the user's telephone and requires potentially large telephone switching equipment resources.
In the field of telephone communications, connections are typically made through the switching system of a telephone exchange and a user's telephone through the medium of a telephone network. When the telephone receiver is lifted off the hook, a loop is formed between the telephone and the exchange's switching system by way of the telephone network, and voice communication is made possible by the transmission of signals around the loop.
As disclosed in Tsumura et al. U.S. Pat. Nos. 5,353,337 and 5,357,505, there are known communications devices which make use of a network's idle time for the unidirectional transmission of broadcast data in the form of, for example, music data to the user's home. This type of communication device calls for the installation in a telephone exchange of an exchange device which is used to switch the telephone network selectively between the switching system-of the exchange itself and a facility installed in an independent center for the transmission of analog data in the form of speech or music. Each user's home is fitted with a home device with a speaker which is connected to the telephone network and which, when the receiver is lifted off the hook, connects the exchange device to the exchange's switching system itself to enable voice communication and, when the receiver is placed on the hook, switches the exchange device to the independent center from which broadcast data is transmitted by way of the telephone network to user's home devices.